The row over last year's firings, which critics in Congress claimed were politically motivated, has been rumbling for months.

Mr Gonzales, the nation's top law-enforcement officer, has faced numerous calls to resign over the affair.

Opponents say he fired the attorneys for political reasons and later lied about the reason for their dismissal.

He testified before committees in both houses of Congress, but senators later said he lied under oath.

Mr Gonzales has repeatedly said that he did nothing wrong.

Phone tapping

In announcing his resignation, Mr Gonzales said: "It has been one of my greatest privileges to lead the Department of Justice."

The son of poor immigrants, Mr Gonzales added that even his worst day as attorney general had been "better than my father's best days".

Mr Gonzales drafted the rules governing Guantanamo Bay

As well as the sackings row, Mr Gonzales has also been criticised for helping to expand presidential powers in connection with the administration's war on terror - from drafting the controversial rules governing prisoners at Guantanamo Bay to authorising a secret phone tapping programme

He was censured by some human rights groups after writing a memo to the president in which he said the war against terror was a "new kind of war" that renders obsolete Geneva's strict limitations on questioning of enemy prisoners and renders "quaint" some of its provisions.

The memo came to light after the Abu Ghraib prison abuse scandal in Iraq.

Latest casualty

Mr Gonzales stuck to his views, although he also made it clear that he did not approve of torture.

Opponents accuse him of bringing about the erosion of civil liberties.

Mr Bush is said to have reluctantly accepted his resignation when it was tendered on Friday, our correspondent says.

HAVE YOUR SAY

In the stance that terrorists are not covered by the Geneva Convention and other hard line advocacy he has been definitely controversial, but also effective